JPH05166249A - Rotary head drum device - Google Patents

Abstract

PURPOSE:To enable the sure discharge of the static electricity generated in a tape at a low cost and to eliminate the noises and loss torque during rotation of a rotary drum. CONSTITUTION:This rotary head drum device has a stationary drum 10 which is fixed via a drum base 3 to a chassis 1, a rotary drum 30 which is freely rotatably supported via a revolving shaft 20 on this stationary drum 10 and projects a head 31 on its outer peripheral surface 30a on which the tape travels and an earth member 40 which is erected in the corner part on the drum base 3 so as to expend onto the rotary drum 30. A conductive brush 46 is mounted via a holder 43 to the front end 42a of a mounting plate 42 of the earth member 40. This conductive brush 46 is formed freely contact with the upper surface of a mounting flange 21 fixed to the revolving shaft 20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary head drum device provided with a grounding member for discharging an electrostatic charge generated on a tape.

[0002]

2. Description of the Related Art In a VTR (video tape recorder) as a magnetic recording / reproducing apparatus, a rotary drum having a head for recording / reproducing a video signal is arranged at a slight inclination from the tape running direction, and is rotated on the tape. A helical scan type rotary head drum device for recording in an oblique pattern is used. This will be specifically described with reference to FIG. 7. Reference numeral 100 denotes a helical scan type rotary head drum device, which includes a fixed drum 110 fixed on a chassis (not shown) and a bearing (not shown) on the fixed drum 110. And an outer peripheral surface 13 on which a tape (not shown) is rotatably supported via a rotary shaft 120 and
A rotary drum 130 having a head 131 projecting from 0a;
The ground member 140 is provided upright on the chassis and extends to the top surface 120a of the rotary shaft 120 protruding from the upper surface of the rotary drum 130. This earth member 14
Reference numeral 0 designates a mounting plate 141 erected on the chassis and a ground plate 142 fixed to the upper surface of the tip of the mounting plate 141.
Attached to the center of the lower surface of the tip of the ground plate 142,
It is composed of a contact terminal 143 which is in a hemispherical shape and is made of carbon, a noble metal or the like, which contacts the top surface 120a of the rotating shaft 120. The outer peripheral surface 13 of the rotary drum 130
The electrostatic charge generated in the tape running on the track 0a is discharged to the chassis side via the ground plate 142 or the like.

[0003]

However, in the conventional grounding member 140 of the above rotary head drum device 100, since the cost of the contact terminal 143 of the grounding member 140 that makes point contact with the top surface 120a of the rotating shaft 120 is high, the rotation is difficult. There is a disadvantage that the cost of the entire head drum device 100 increases. Further, since the contact terminal 143 always slides in pressure contact with the top surface 120a of the rotating shaft 120 by the spring force of the earth plate 142 of the earth member 140, the contact terminal 143 is rotated by the rotation of the rotary drum 130. The ground plate 142 vibrates to generate noise, the contact terminals 143 wear, and the load increases (loss torque increases) when the rotating drum 130 rotates.

Therefore, the present invention provides a rotary head drum device capable of discharging static electricity generated on a tape reliably and at low cost and eliminating noise and loss torque when the rotary drum rotates. is there.

[0005]

A fixed drum fixed to a chassis, a rotary drum rotatably supported on the fixed drum via a shaft, and a head protruding from an outer peripheral surface on which a tape runs, and a rotary drum In a rotary head drum device provided with a grounding member standing upright on the chassis so as to extend onto a drum, a conductive fiber is provided at a tip of the grounding member, and the conductive fiber is provided on the shaft or the rotary drum. It can be touched on top.

[0006]

Since the conductive fiber provided at the tip of the earth member is allowed to come in contact with the shaft or the rotating drum, the electrostatic charges generated on the tape are discharged to the chassis side reliably and at low cost. There is no noise and loss torque when the rotating drum rotates.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

In FIG. 1, reference numeral 1 denotes a helical scan type rotary head drum device, which is used for an 8 mm VTR as a magnetic recording / reproducing device. This rotary head drum device 1 includes a fixed drum 10 fixed to a chassis 2 via a drum base 3, and a fixed drum 10
An outer peripheral surface 3 on which a tape (not shown) is rotatably supported by a bearing (not shown) and a rotating shaft 20 and
0a, a rotary drum 30 having a head 31 protruding therefrom, and a ground member 40 provided upright on the drum base 3 and protruding to an upper surface 30b of the rotary drum 30 and extending to the top surface 20a side of the rotary shaft 20. There is.

The ground member 40 has a mounting base 41 shown in FIG. 3 having a bottom portion 41a screwed to a corner portion on the drum base 3, and a rising portion 4 of the mounting base 41.
The upper surface 30b of the rotary drum 30 is screwed to 1b.
The mounting plate 42 shown in FIG.
5, a holder 43 fixed to a tip end portion 42a bent and formed with a screw 44, a U-shaped tip end portion 43a side of the holder 43 is caulked and fixed to an upper portion of the rotary shaft 20. The conductive fiber (metal fine wire, metal plated fiber,
And a conductive brush 46 made of carbon fiber or the like). This holder 43 is made of aluminum,
A positioning pin 45 is planted approximately at the center thereof. When the holder 43 is fixed to the distal end portion 42a of the mounting plate 42 with the screw 44, the positioning pin 45 moves the mounting plate 42.
When the holder 43 is fitted into the positioning hole 42b formed in the tip portion 42a of the mounting plate 42,
2a is positioned and fixed at a predetermined position. The rotary drum 30 is fixed to the mounting flange 21. The rotary shaft 20 to which the mounting flange 21 is fixed is composed of a motor shaft (not shown),
The rotary drum 30 is rotated by driving this motor.

According to the rotary head drum device 1 of the above embodiment, the static electricity generated on the tape running on the outer peripheral surface 30a of the rotary drum 30 is caused by the conductive brush 4 of the ground member 40.
It is discharged to the chassis 2 side via 6 and the like. Since the conductive brush 46 of the grounding member 40 is made of conductive fiber, the grounding member 40 can be manufactured at low cost, and the load thereof does not increase when the rotary drum 30 rotates. As a result, the electric charge of static electricity that tends to stay on the rotating drum 30 side from the tape can be surely discharged to the chassis 2 side via the conductive brush 46 of the earth member 40 and the drum base 3.
Electrostatic charges generated on the tape are not accumulated on the rotary drum 30 and the head 31, and jitter or the like does not occur during recording or reproducing.

Further, as in the prior art, the rotary drum 30 is
When rotating the, the mounting plate 41 of the ground member 40, the holder 42
Etc. will not vibrate and no noise will be generated.
Further, even if the rotary head drum device 1 is downsized,
The ground member 40 can be easily assembled, and the assembly processing cost can be reduced.

According to the above-mentioned embodiment, the conductive brush made of the conductive fiber of the grounding member is made to contact the mounting flange fixed to the rotary shaft. You may make it contact an upper surface. Even when the conductive brush is in contact with the upper surface of this rotating drum,
The load does not increase when the rotating drum rotates. Further, although the earth member is composed of the mounting base, the mounting plate, the holder and the conductive brush, the mounting base, the mounting plate and the holder are formed of one metal plate, and the tip of this one plate is formed. Alternatively, the conductive brush may be fixed by crimping.
Further, the rotary drum mounted on the rotary shaft has been described. However, it is needless to say that the embodiment can be applied to a rotary shaft rotatably supported by a fixed shaft fixed to the fixed drum via a bearing. ..

[0013]

As described above, according to the rotary head drum device of the present invention, the fixed drum fixed to the chassis and the outer periphery on which the tape is rotatably supported by the fixed drum via the shaft. In a rotary head drum device including a rotary drum having a head protruding from a surface thereof and a grounding member erected on the chassis so as to extend onto the rotary drum, a conductive fiber is provided at a tip of the grounding member. Since the conductive fiber is configured to come into contact with the shaft or the rotary drum, static electricity generated in the tape running on the outer peripheral surface of the rotary drum can be surely discharged to the chassis side. Further, since it is only necessary to provide an inexpensive conductive fiber at the tip of the earth member, the earth member and the rotary head drum device as a whole can be manufactured at low cost. Further, even if the conductive fiber of the earth member is in contact with the rotating drum or the like, the load thereof does not increase when the rotating drum is rotated, and the conductive fiber is hardly worn, so that high-precision rotation is possible. A head drum device can be provided.

[Brief description of drawings]

FIG. 1 is a side view of a rotary head drum device showing an embodiment of the present invention.

FIG. 2 is a plan view of the rotary head drum device.

FIG. 3 is a plan view of a mounting base of a grounding member used in the rotary head drum device.

FIG. 4 is a front view of a mounting plate for the ground member.

FIG. 5 is a plan view of the holder of the earth member.

FIG. 6 is an exploded perspective view of the holder of the earth member and a conductive brush.

FIG. 7 is a perspective view of a conventional rotary head drum device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Rotating head drum device, 2 ... Chassis, 10 ... Fixed drum, 20 ... Rotating shaft, 30 ... Rotating drum, 30a ... Outer peripheral surface, 31 ... Head, 40 ... Ground member, 46 ... Conductive brush (conductive fiber) ..

Claims (1)

[Claims] 1. A fixed drum fixed to a chassis, a rotary drum rotatably supported on the fixed drum via a shaft, and having a head protruding from an outer peripheral surface on which a tape runs,
In a rotary head drum device provided with a grounding member erected on the chassis so as to extend onto the rotary drum, a conductive fiber is provided at a tip of the grounding member, and the conductive fiber is provided on the shaft or on the shaft. A rotary head drum device characterized in that it is freely contactable on a rotary drum.